The present invention relates to a piercing device for piercing ventilating holes in cigarettes or similar smoking commodities.
For making so-called "ventilated" cigarettes, piercing devices are known to be employed on which the piercing "tool" consists of a laser source. On known types of laser beam piercing devices, cigarettes are generally pierced according to two techniques, the first using a laser source which pierces the said ventilating holes in the cigarettes as they turn round their own axis, and the second using mobile reflecting systems designed to divert the laser beam on to the cigarette being pierced in different directions, while the cigarette travels in relation to the said source without turning round its own axis.
In both the above cases, known types of laser beam devices use a "pulsating" laser source the frequency of which is such as to pierce a hole for each pulse.
The employment of a pulsating laser source, however, makes it practically impossible for the above known types of piercing devices to be used in conjunction with high-output cigarette manufacturing or filter assembly machines designed for producing as many as 10,000 cigarettes a minute.
For this to be done, the pulse frequency required for piercing about thirty holes in each cigarette is around 5,000 Hz, which means using relatively large, high-power laser sources. Furthermore, such pulse frequencies usually result in irregular, drawn-out holes of unacceptable appearance.